Density indicating apparatus



' Jan. 1, 1957 E. R. NETT DENSITY INDICATING APPARATUS Filed Dec. 7,1953 INVENTOR. Eruaezr 2. NET? BY W WWW zflzforne .5

United States Patent 07 2,775,893 DENSITY INDICATING APPARATUS EthbertR. Nett, Beverly Hills, Calif. Application December 7, 1953, Serial No.396,446

8 Claims. (Cl. 73434) Y The present invention relates generally toapparatus for indicating the density of a flowing fluid and moreparticularly to an apparatus adapted to provide a continuous indicationof the density of oil well drilling mud.

In drilling an oil well by the rotary method, drilling mud is circulateddownwardly through the drill pipe string and upwardly through theannular space surrounding the drill pipe string and the sidewalls of thebore hole. The drilling mud serves to remove the cuttings from the wellbore and to prevent caving of the sidewalls ofthe well byprovidingsuflicient hydrostatic pressure to overcome the pressure of the earthformations being penetrated by the drill bit. Close control of thedensity of the drilling mud is required throughout the drillingoperation. It is necessary on the one hand that the weight of thedrilling 'mud be suflicient to provide a hydrostatic pressure adequateto retain fluids, such as gas or water, within their formations in orderto prevent a possible blow out from occurring; 'on the other hand, ifthe drilling mud becomes tooheavy, it may be continuously forced intoone or more of the formations being penetrated so as to result in thecondition known as lost circulation. Accordingly, 'it isnecessary duringthe course of the drilling operation 'to'frequently adjust the weight ofthe drilling mud by adding thereto Weighting materials or by increasingits fluid content, It will therefore be apparent that a cont nuous andaccurate indication of the mud density during the drilling operation isboth desirable and necessary.

' While there have been heretofore proposed various types of mud densityindicating devices, these have proven to be generally unreliable andinaccurate in use. The inaccuracy of such devices has been due, inmostcases, to the accumulation of suspensoids, usually solids, on themovable part of thedevice which actuates the scale member thereof. Otherheretofore-proposed types of mud density indicating devices, whileaifording comparatively accurate results, are of a complex, costly andoften bulky nature whereby they have failed to meet with widespreadacceptance in the oil well trade.

It is a major object of the present invention to provide densityindicating apparatus which will afford extremely accurate results for acomparatively long period. of time without requiring any maintenance.

"Another object is to provide density indicating apparatus whichutilizes the torsional deflection of a tubular fluidcarrying member toobtain a measurement of the density of such fluid..

further object of the invention is to provide appajratusof this naturewhich is extremely simple of design and-rugged of construction wherebyit may afford a long and trouble-free service life.

An additional object is to provide density indicating apparatus which iscomparatively small and compact whereby it may be readily portable. Yetanother object is to provide apparatus of this nature which isinexpensive to construct.

A further object is to provide density indicating apparatus throughwhich the mud to be weighed may flow without requiring any type ofsealing device.

2,775,893 Patented Jan. 1, 1957 Yet an additional object of theinvention is to provide apparatus of this nature which is capable ofproviding accurate measurements regardless of the pressure and velocityof the fluid being measured.

These and other objects and advantages of the present invention willbecome apparent from the following detailed description, when taken inconjunction with the appended drawings wherein:

Figure 1 is a generally schematic, perspective view of a preferred formof density indicating apparatus embodying the present invention;

Figure 2 is an enlarged fragmentary, central vertical sectional view ofsaid apparatus; and

Figure 3 is a fragmentary sectional view similar to Figure 2 but showingan alternate embodiment of said apparatus.

Referring to the drawings, the preferred form of density indicatingapparatus embodying the present invention broadly comprises asubstantially horizontally disposed main fluid conduit, generallydesignated 10, having one of its ends rigidly secured to a frame member,generally designated 12. First and second auxiliary conduits, 14 and 16,respectively, extend away from one side of the main conduit 10, in asubstantially horizontal direction. A weighing container 18 isinterposed between the ends of the first and second auxiliary conduits.An indicating mechanism, generally designated 20, is operativelyconnected to the weighing container 13. The interior of the main conduit10 is formed with means to be fully described hereinafter for constantlycirculating a fluid to be weighed through the first and second auxiliaryconduits and the weighing container 18. The presence of such liquid inthe Weighing container will exert a downward force upon the end of themain conduit remote from the frame member 12 by means of the auxiliaryconduits so as to eifect a'torsional deflection or twisting of the mainconduit relative to theframe member. The exact amount of such torsionaldeflection is proportional to the Weight of the increment of fluidpresent in the weighing container at a given time. The indicatingmechanism 20 serves to amplify the effect of such torsional deflectionand convert it into desired sealer measurements.

More particularly, and with special reference to Figure 2, the mainconduit 10 is of tubular cross-section and is rigidly secured as bywelding within an aperture 30 formed in the frame member. The front endof the main conduit is closed by a vertical wall 32, while its rear endis closed by a plug 34 wherein is formed a coaxial bore 36. An innertubular member 38 is coaxially disposed Within the main conduit 10 so asto isolate its interior into separate front and rear chambers,designated 40 and 42, respectively. The front end 39 of the innertubular member 38 is flared radially outwardly and is in close proximityto the inner periphery of the main conduit at this point. The rearportion of this tubular member 38 is carried within the bore 36 of theplug 34. i

The first and second auxiliary conduits 14 and 16 are preferably oftubular cross-section and are rigidly secured as by welding withinapertures 44 and 46 respectively, formed at spaced points within themain conduit. A downwardly extending discharge conduit 48 is shownrigidly secured'within an aperture 50 formed in the rear chamber 42 ofthe main conduit.

The weighing container 18 is shown as being of cylindrical configurationhaving its top and bottom portions secured to the ends of the auxiliaryconduits l4 and 16 remote from the main conduit. With this arrangement,as indicated by the directional arrows in Figures 1 and 2, the fluid tobe weighed enters the front chamber 40 of the main conduit by means ofthe inner tubular member 38. This fluid then flows outwardly through thefirst auxiliary conduit 14 into the bottom of the weighing contamer-18'and upwardly therethrough into the'outer end of the second auxiliaryconduit 16. Next, this fluid returns through the latter auxiliary,conduit into the rear chamber 42 of the maid conduit, leaving thischamber through the discharge conduit 48; Thusfthe fluid to be weighedis caused to constantly circulate through the main conduit, theauxiliary conduits, and the weighing conduit.

During such circulating action, the weight of the fluid within theweighing container and the first and second auxiliary conduits willeffect a torsional deflection of the main conduit and a subsequentdownward movement of the weighing container 13. The pointer 54 of theindicating mechanism 20 is pivotally secured to a fixed point relativeto the frame member 12 by a pivot pin 56; and inasmuch as this point inturn pivotally connected to the weighing container by a rod 58, its freeend 60 will move along the scale 62. During such movement the free end60 of the pointer will assume, for purposes of maximum deflection, aposition adjacent the scale reading l50# in Figure 1. It will beapparent that the scale 62 may be readily calibrated to read directly interms of both fluid weight and density. It will be further apparent thatvarious other forms of mechanical or electrial indicating mechanism maybe utilized without departing from the scope of the present invention.

Referring now to Figure 3, there is shown an alternate embodiment of adensity indicating apparatus embodying the present invention. Thisembodiment includes a main conduit wherein is concentrically disposed aninner tubular memberSS' of smaller diameter. The radially outwardlyflared front end 39 of the inner tubular member 38' is rigidly securedto the inner periphery of the main conduit as by welding. The rear endof the main conduit 10 is spaced from the frame member 12 in thisembodiment and the main conduit is attached thereto solely by means ofthe inner tubular member 38'. Thus, the latter is rigidly secured withinan aperture 30 formed in the frame member as by welding. The innertubular member serves to isolate the interior of the main conduit 10'into separate chambers designated 40 and 42'.

The first and second auxiliary conduits 14 and 16, as well as theweighing container (not shown), and the indexing mechanism (not shown)may be of similar construction to their counterparts describedhereinbefore in conjunction with Figures 1 and 2. The rear end of themain conduit 10 is open, as indicated at 70, whereby as shown by thedirectional arrows, fluid to be weighed may be discharged therethroughinto the top of an open discharge-receiving receptacle 72.

The operation of this alternate embodiment is substantially the same asthat heretofore described with respect to the preferred embodiment. Thefluid to be weighed enters the front chamber 40 of the main conduit 10'by means of the inner tubular member 38. This fluid, after circulatingthrough the first auxiliary conduit, the weighing container, and thesecond auxiliary conduit, returns to the rear chamber 42 of the mainconduit. Finally, this fluid is discharged through the rear end of themain conduit and enters the receptacle 72.

Although the alternate embodiment incorporates an open fluid systemrather than the closed fluid system contemplated by the preferredembodiment, if it is necessary or desirable that such system be closed,the rear end of the main conduit 10 may be provided with a suitablerotary seal and a discharge pipe connected with such seal. In thismanner the discharge pipe may be placed in closed communication with theflow of the fluid being measured.

It should be noted that by virtue of the reduced diameter of the innertubular member 38 of the alternate embodiment, as compared with thediameter of the main conduit 10 of the preferred embodiment, for a givenchange in weight of the fluid being measured, greater torsionaldeflection of the tubular member 38 will occur than will take place withthe main conduit 10. Accordingly, it is possible to construct a morecompact density indicating apparatus for the same range of accuracywhere the alternate embodiment of the invention is utilized.

While the weighing container 18 is shown as being of generallycylindrical configuration in the appended drawings, it should beobserved that the shape of this bottle may be so selected as to providefor self-cleaning thereof by means of the natural turbulence createdtherein by the fluid being measured. Both embodiments of the .inventiondescribed herein provide simple and practical apparatus which mayreadily be made portable in nature and easily assembled in the field bythe oil well drilling crew.

While there has been shown and described a preferred and alternateembodiment of the present invention, it will be apparent that variousmodifications and changes may be made without departing from the spirit,of the invention or the scope of the following claims.

I claim:

1. Apparatus for indicating the density of a fluid, com.- prising: aframe member; a substantially horizontally disposed tubular main conduitsupported by said frame member; first and second auxiliary conduitsrigidly connected to said main conduit and extending away'fro'm one sideof said main conduit in a substantially horizontal die,- rection; meansconnecting said auxiliary conduits together at their ends remote fromsaid main conduit for fluid flow therethrough from one auxiliary conduitto the other; an inner tubular conduit coaxially disposed within saidmain conduit and isolating the interior thereof into two separatecoaxial chambers, the first auxiliary conduit being in communicationwith one of said chambers and the second auxiliary conduit being incommunication with the other of said chambers whereby a fluid to beweighed may pass from one of said chambers to the other by means of thesaid auxiliary conduits; and indicating means operatively connected tosaid auxiliary conduits and responsive to movement thereof resultingfrom torsional deflection of one of said coaxial tubular conduits.

2. Apparatus for indicating the density of a fluid, comprising: a framemember; a substantially horizontally disposed tubular main conduitrigidly secured at its rear portion to said frame member; first andsecond rigid auxiliary conduits rigidly connected to said main conduitand extending away from one side of said main conduit in a substantiallyhorizontal direction; means connecting said auxiliary conduits togetherat their ends remote from said main conduit for fluid flow therethroughfrom one auxiliary conduit to the other; an inner tubular conduitcoaxially disposed within said main conduit and iso lating the interiorthereof into two separate longitudinally spaced coaxial chambers; andthe first auxiliary conduit being in communication with one of saidchambers-and the second auxiliary conduit being in communication withthe other of said chambers whereby a fluid to be weighed may pass fromone of said chambers to the other by means of the said auxiliaryconduits; and indicating meansoperatively connected to said auxiliaryconduits and responsive to movement thereof resulting from torsionaldeflection of one of said coaxial tubular conduits. I

3. Apparatus for continuously indicating the density of a flowing fluid,comprising: a frame member; a substantially horizontally disposedtubular main conduit rigidly supported by said frame member; a dischargeopening formed in the rear of said main conduit; first and secondauxiliary conduitsrigidly connected to said main conduit and extendingaway from one side of said main conduit in a substantially horizontaldirection at points spaced forwardly of the point of connection ofsaidmain conduit to said frame member; a weighing container interposedbetween the ends of said auxiliary conduits remote from said mainconduit; an inner tubular member coaxially disposed within said mainconduit, said tubular member having a radially outwardly extending frontend that abuts the inner periphery of said main conduit and isolates theinterior thereof into front and rear chambers, the first auxiliaryconduit being in communication with one of said chambers and the secondauxiliary conduit being in communication with the other of said chamberswhereby a fluid to be weighed may enter said first chamber through saidinner tubular member, pass from said front chamber to said rear chamberby means of said auxiliary conduits and said weighing container, thenflow out of said rear chamber through said discharge opening; and anindicating mechanism operatively connected to said weighing containerand responsive to the movement thereof resulting from the Weight offluid passing through said auxiliary conduits and saidweighing-container.

4. Apparatus for continuously indicating the density of a flowing fluid,comprising: a frame member; a substantially horizontally disposedtubular main conduit rigidly supported by said frame member; a dischargeopening formed in the rear of said main conduit; first and secondauxiliary conduits rigidly connected to said main conduit and extendingaway from one side of said main conduit in a substantially horizontaldirection at points spaced forwardly of the point of connection of saidmain conduit to said frame member; a weighing container interposedbetween the ends of said auxiliary conduits remote from said mainconduit, the average cross-sectional area of said container beingconsiderably greater than that of said auxiliary conduits, and the topand bottom portions of said container being in communication with saidends; an inner tubular member coaxially disposed within said mainconduit, said tubular member having a radially outwardly extending frontend that abuts the inner periphery of said main conduit and isolates theinterior thereof into front and rear chambers, the first auxiliaryconduit being in communication with one of said chambers and the secondauxiliary conduit being in communication with the other of said chamberswhereby a fluid to be weighed may enter said first chamber through saidinner tubular member, pass from said front chamber to said rear chamberby means of said auxiliary conduits and said weighing container, thenflow out of said rear chamber through said discharge opening; and anindicating mechanism operatively connected to said weighing containerand responsive to the movement thereof resulting from the weight offluid passing through said auxiliary conduits and said weighingcontainer.

5. Apparatus for continuously indicating the density of a flowing fluid,comprising: a frame member; a substantially horizontally disposedtubular main conduit rigidly supported at one point along its length; adischarge opening formed in the rear portion of said main conduit; firstand second auxiliary conduits rigidly connected to said main conduit andextending away from one side of said main conduit in a substantiallyhorizontal direction at points spaced forwardly of the point ofconnection of said main conduit to said frame member; a weighingcontainer interposed between the ends of said auxiliary conduits remotefrom said main conduit, the average crosssectional area of saidcontainer being considerably greater than that of said auxiliaryconduits, and the top and bottom portions of said container being incommunication with said ends; an inner tubular member coaxially disposedwithin said main conduit, said tubular member having a radiallyoutwardly extending front end that abuts the inner periphery of saidmain conduit and isolates the interior thereof into front and rearchambers, the first auxiliary conduit being in communication with one ofsaid chambers and the second auxiliary conduit being in communicationwith the other of said chambers whereby a fluid to be weighed may entersaid first chamber through said inner tubular member, pass from saidfront chamber to said rear chamber by means of said auxiliary conduitsand said weighing container, then flow out of said rear chamber throughsaid discharge opening; and

6 an indicating mechanism operatively connected'to said weighingcontainer and responsive to the movement thereof resulting fromthetorsional deflection of the main conduit relative to the frame memberdue to the weight of the fluid passing through said auxiliary conduitsand said weighing container. l p

6. Apparatus for continuously indicating the density of a flowing fluid,comprising; a frame member formed with an aperture; a substantiallyhorizontally disposed tubular main conduit rigidly secured at its rearportion within said aperture; a discharge opening formed in the rearportion of said main conduit; first and second auxiliary conduitsrigidly connected to said main conduit and extending away from one sideof said main conduit in a substantially horizontal direction at pointsspaced forwardly of the point of connection of said main conduit to saidframe member; a weighing container interposed between the ends of saidauxiliary conduits remote from said main conduit; an inner tubularmember coaxially disposed within said main conduit, said tubular memberhaving a radially outwardly extending front end that abuts the innerperiphery of said main conduit and isolates the interior thereof intofront and rear chambers, the first auxiliary conduit being incommunication with one of said chambers and the second auxiliary conduitbeing in communication with the other of said chambers whereby a fluidto be weighed may enter said first chamber through said inner tubularmember, pass from said front chamber to said rear chamber by means ofsaid auxiliary conduits and said weighing container, then flow out ofsaid rear chamber through said discharge opening; and an indicatingmechanism operatively connected to said weighing container andresponsive to the movement thereof resulting from the torsionaldeflection of the main conduit relative to the frame member clue to theweight of the fluid passing through said auxiliary conduits and saidweighing container.

7. Apparatus for continuously indicating the density of a flowing fluid,comprising: a frame member; a substantially horizontally disposed mainconduit formed with a discharge opening at its rear portion; first andsecond auxiliary conduits rigidly connected to said main conduit andextending away from one side of said main conduit in a substantiallyhorizontal direction; a weighing container interposed between the endsof said auxiliary conduits remote from said main conduit; an innertubular member disposed Within said main conduit and having its rearportion rigidly secured to said frame member; a radially outwardlyextending front end formed on said inner tubular member having its outerextremity rigidly secured to the inner periphery of said main conduitand isolating the interior thereof into separate front and rearchambers, the first auxiliary conduit being in communication with one ofsaid chambers and the second auxiliary conduit being in communicationwith the other of said chambers whereby a fluid to be weighed may entersaid first chamber through said inner tubular member, pass from saidfirst chamber to said rear chamber by means of said auxiliary conduitsand said weighing container, then flow out of said rear chamber throughsaid discharge opening; and an indicating mechanism operativelyconnected to said weighing container and responsive to the movementthereof resulting from the torsional deflection of said inner tubularmember relative to said frame member due to the Weight of fluid passingthrough said auxiliary conduits and said weighing container.

8. Apparatus for continuously indicating the density of a flowing fluid,comprising: a frame member formed with an aperture; a substantiallyhorizontally disposed tubular main conduit having its rear end open andspaced longitudinally forwardly of said frame member, said open rear endforming a discharge opening; first and second auxiliary conduits rigidlyconnected to said main conduit and extending away from one side of saidmain conduit in a substantially horizontal direction; a weighing.container interposed between the ends ofsaid-auxiliary:conduitsremotefrom said main conduit, the averagecross-sectional area of said container-being considerably greater thanthat of said auxiliarytconduits, and the top ,and bottom -portionsof-said container being in communication with said ends; an innertubular memberdisposed within said main conduit and having its rearportion rigidly secured to said frame member; a radially outwardlyextending front end formed on said inner tubular member having its outerextremity rigidly secured to the inner periphery of said main conduitand isolating the interior thereof into separate front and rearchambers, the first auxiliary conduit ;being in communication with oneof said chambers and the second auxiliary conduit being in communicationwith the other of said chambers whereby a fluid to be weighed may entersaid first chamber through said inner tubular member, pass from saidfront chamber to said reanchamber by means of said auxiliary conduitsand said weighing container, then flow out of said rear chamber throughsaid discharge opening; and an 'indicating'mechanism having a pointerthat is pivotally mounted to a fixed point relative to said frame, and arod pivotally interconnecting said pointer and said weighing container.

References Cited in the file of this patent UNITED STATES PATENTS

